The invention relates to a system for aiding a forklift truck operator in aligning the forks on the truck with a pallet to eliminate or minimize damage of the pallet.
In the warehouse and shipping industries, pallet damage from fork trucks is a major and costly concern. Motorized forklifts are the principal means of moving industrial products, and are also the principal cause of damage to products and especially to the pallets upon which the products are placed. This damage occurs because forklift operators do not have visual access to the target area for the forks.
The known prior art relative to this technology is represented by U.S. Pat. Nos. 4,279,328, 4,678,329, 4,604,025, 3,854,820, 3,854,820, 4,566,032, 3,700,907, 4,549,845, and 4,724,480.
U.S. Pat. No. 4,678,329 is directed to a navigation system for movement of a vehicle to the vicinity of a pallet and does not describe the operation of the vehicle at the pallet. The system appears to be an autonomous system set up to navigate the vehicle without operator aid and without movement of the forks.
U.S. Pat. No. 4,279,328 relates to a forklift truck orientation system based on a remote controlled vehicle guided, for example, by a wire in the floor for precise handling orientation such as in robotic systems.
U.S. Pat. No. 4,604,025 discloses a "line of sight" aid for an operator of a "mobile material handling machine"; electronics or an imaging system are not included in the description.
U.S. Pat. No. 3,854,820 (Re. 29,025) relates to a light referencing system including a light source used to generate a collimated beam of light and converting and projecting the same as a relatively intense fan-shaped or diverging plane of light from an operator manipulatable device on a machine or vehicle to an object, such as a pallet. The system includes no imaging or electronics.
U.S. Pat. No. 4,566,032 discloses an unmanned vehicle which is optically guided. A guide belt laid on the floor guides the vehicle. A vehicle camera receives light reflected from the guide belt.
U.S. Pat. No. 3,700,907 describes a very complex optically-based system for identifying an object or the identification of the contents of a moving or stationary object.
U.S. Pat. No. 4,549,845 concerns the special modification of a material handling vehicle to handle and/or manipulate drums.
U.S. Pat. No. 4,724,480 uses a light pattern projected from a first object onto a second object, and an image of the pattern of light on the second object is recorded with a camera mounted on the first object. This system appears to be applicable to a robot end effector and uses circles of light to determine distance and orientation.